已知-π⼀2<x<0 tanx=-2 (1)求sinx-cosx的值

(2)求sin(360-x)cos(180-x)-sinx2/cos(180+x)cos(90-x)+cos^2x的值求过程
2025-05-10 09:23:15
推荐回答(1个)
回答1:

(1)tanx=-2 π/20
sinx=-2/根号(5) cosx=1/根号(5)
sinx-cosx=-3/根号(5)
(2)sin(360-x)cos(180-x)-sinx2/cos(180+x)cos(90-x)+cos^2x
=-sinx*(-cosx)-2sinx*cosx/((-cosx)*sinx)+cos^2x
=sinx*cosx+2+cos2x/2+1/2
=sin2x*/2+2+cos2x/2+1/2
=根号(2)sin(2x+pi/4)+5/2